The pumping of expensive and valuable liquid into an object typically requires the close monitoring of the pump system to detect any leak or failure in the system to avoid the resulting loss of the expensive and valuable liquid. For example, in order to cure or prevent a tree disease known as oak wilt, a fungicide must be injected into the root system of a tree. The fungicide is typically injected through tubing and "T" shaped nozzles into the root system around the base of the tree. However, the fungicide associated with the treatment of oak wilt is quite expensive. Therefore, it is extremely important that the pump system be promptly stopped or deactivated in the event of a liquid leak. For example, it is extremely important that the system be stopped or deactivated in the event of a break in the tubing or dislodgment of one or more fittings from the tree during application of the fungicide. Also, it is desirable to automatically deactivate the system if the fungicide reservoir becomes empty.
In the absence of a system for automatically shutting down the pump system in the event of a leak or failure, the expensive fungicide must be applied at extremely low pressures and/or the pump system must be visually monitored during application of the fungicide to allow the pump system operator to manually deactivate the system in the event of a liquid leak or failure. These alternatives are time consuming and expensive and therefore extremely undesirable.